E36 coolant temp sensor in LS1

[M5Hunter]

I'm curious what others have done to use the factory BMW coolant temp sensor in thier LSx swaps. Obviously the GM temp sensor goes in the drivers side head at the front and there is a plugged port at the rear of the passenger side head. I spoke with Fair vai email and he said they just stick the BMW sensor in that hole. My BMW sensor is too big to use there. I see that Nash's instructions on thier website said you need a m10 to m12 adapter. I called Nash and they said that they dont have them anymore because no one makes them anymore. Do different year cars have different sensors or do different LSx heads have bigger threaded holes?

thanks

HERE ARE THE ANSWERS FOUND IN THIS THREAD

Ok so there are X number of ways to go about this:

*Of if you already have a 3/8 NPT tap, you could use the JTR adapter linked below that specifically fits the early BMW temp sender.
http://www.jagsthatrun.com/Pages/Par...mpSending.html

*purchase a 14mm tap and corresponding drill bit then open up and tap the threaded hole in the LSx to accept the 14mm sensor.

*Mill down the sensor threads and re-thread it to to m12x1.5

*It does look like the '96 and newer sensor will work, but it has a 4 prong connector rather than the 2.

Update!
First off, thank you to Pzary for his help.

Water temp sendors AND sensors, BMW EFI, BMW Gauge and LSx, measured, (Senders and sensors tested were BMW BOSCH connection/square 2 prong; Black top, Green Top, Brown/Tan top, 4 prong prong round top, early Datsun EFI and GM LSx. Of interesting note is that all the BMW 2 prong EFI and Datsun EFI sensors were within 2% of each tother from 60-20 degrees F).

First the good news.
The resistance values-vs-temp values for the instrument gauges on ALL E36 cars, '92-'99 are the same! We all have been speculating they were different, come to find out they aren’t. BMW originally utilized two separate sensors/senders, (one for the EFI, other for the gauge), on the ’92-’95 cars then in ‘96 combined them into one housing for the later cars, the 4 prong sensor/sender and retained the same exact values for both DME and gauge.

Now the great news!
What that means for anyone doing the 92-’99 E36, (318, 323, 325, 328, M3,) LSx conversion is the ’96+ 4 prong sensor/sender works with their gauge and threads directly into the LSx head, no drilling, tapping, bushings, adapters etc to use the earlier 2 prong sensor, unless you want to. Just deduce which 2 prongs for the gauge, (easy to do with the Bentley manual and an OHM meter), and you’re there.

As for the pig tail, many other BMW’s used this same connector, easy to find in wrecking yards on other cars.

The just ho-hum news.
The LSx PCM sensor has a slightly different curve/slope compared the BMW EFI temps sensor, enough so that you wont want to use the BMW DME sensor for the LSx PCM, (see chart below). One could possibly adjust the CLT values using one of the tuning suites, I am pretty sure it’s just easier to install the GM temps sensor in the other head and be done with it. For what it’s worth, ALL GM temp sensors coolant and air temp have the same resistance to temp values, across the board, Pontiac, Olds, Chevrolet, etc, applicable to all GM Multi Port EFI vehicles.


LEGEND!
X axis= Degrees Fahrenheit.
Y axis = resistance in OHMS.
BMW EFI I = OBD-I DME temp sensor.
BMW EFI II = OBD-II DME temp sensor.
BMW Gge I = OBD-I gauge temp sender.
BMW Gge II = OBD-II gauge temp sender.
LSx EFI = PCM temp sensor.




As mentioned earlier, There is a down side to these BMW temp gauges. I spent a bit of time researching this and here is what I found.
BMW incorporated some form of buffer within the instrument cluster itself that holds the temp needle straight up, middle of the gauge when the engine is between 140-230ish degrees F. If the coolant temp breaches 230-ish then the gauge will swing from the middle up to HOT, not an incremental climb as one would expect or hope for as the engine gets warmer. The sender itself is analog like any other sender for a temp gauge, this buffering is done in the instrument cluster. Some feel the Euro cluster has less of a buffer but I was not able to find any evidence to support or deny that claim. There is a bit of speculation as to why BMW did this, turning a perfectly useful analog gauge into useless cold hot dial, beneficial no one. (theories such a people are getting so stupid that when they wee gauge move from center they panic and take their car to the dealer so this prevents unnecessary warranty claims, etc). Regardless, I see no point in trying to figure out why BMW did this, it is what it is, any discussion should really be centered around a possible solution to obtain a true analog temp gauge. Some have talked about trying to remove the buffer in the instrument itself, others have successfully replaced the internal guts of the temp gauge with VDO guts, stock needle and now have a gauge that indicates temperature on an analog scale. If someone finds a way to eliminate the buffer itself or other way so to get around this, please share, for now, here is what I found;


The issue, for those interested in reading;
http://forums.bimmerforums.com/forum/showthread.php?t=1208832

http://forums.bimmerforums.com/forum/showthread.php?t=1480682

http://m3forum.net/m3forum/showthread.php?t=324399

Fixes;
http://forums.bimmerforums.com/forum/showthread.php?t=1105631

http://forums.bimmerforums.com/forum/showthread.php?t=776813


Hope this helps someone.

Here are the pins to use (Looking at the connector's end. X20 pins based on 1996 328is):


Connector Part # 12521703571 - Need One
Connector Pins # 61130007657 - Need Two (usually comes with short wire and seal)

[mateo m3]

if you search in this section i think someone cover this sometime ago, i think that you need the sensor from a 96+ and it will bolt right up, i think, just double check to make sure

[M5Hunter]

good call, was able to locate it finally. It does look like the '96 and newer snesor will work, but it has a 4 prong connector rather than the 2, so my harness wont work with it. The motor is in the car, so no drilling and tapping is possible. I guess I'll figure something out.

thanks

[Pzary3233]

If you don't want to find an OBDII harness and hack off the connector, you could just buy this:


http://egauges.com/vdo_indS.asp?Send...VDO&PN=323-088
And then ground the grounding wire....

That should work as well...

[M5Hunter]

the factory bmw gauge will be in the range with this sender for sure? If so, I'm in.

[Pzary3233]

That I do not know for certain, you could measure your ohm readings of your OBDI sending unit then call the VDO...?

Granted VDO made the e36 cluster soo.... Maybe just give them a call?

[Volcom8190]

There is an adapter out there for obd2 to 1 conversions that splits the obd2 sensor into 2 outputs, I think its at the top of this section.

[Pzary3233]

I'd say just get the correct sensor and pigtail, then the extra side can be used for a REAL temp gauge.

Taken from that thread above:

http://homepage.mac.com/aceves/OBDI/OBD_ONE3.htm

Read that page and you'll have everything you need.

[rao]

The factory e36 sensor fits right into the passenger side head on any LS1 -I am not sure why everyone wants to make things so complicated.

[bimerok]

I just checked this on Monday. I have 96 and the sensor does bolt right up to the LS1 head with no problems. 96+ do come as dual temp switch where unlike 95- it is one sensor with 4 pins- two go to the ECU and the other two go to the temp guage. Not to reuse one I had in my m52, I just ordered a new sensor and connector with pins. The total was around $40 for everything with shipping.

I also heard that 96+ and 95- do read differently and can be off by some amount when mixed.

Another option is to use adapter. I believe this is what you might need. Perhaps you can contact them to make sure: Click Here For Adapter

[Pzary3233]

The reason some make a deal about it is because they do not have the coolant temp sensor for a 96+ m50 nor do they have the pig tail.

[rao]

In the context of an engine swap getting a sensor and pigtail is not a big deal and makes the finished product a lot better, but to each his own.

[Pzary3233]

I just checked this on Monday. I have 96 and the sensor does bolt right up to the LS1 head with no problems. 96+ do come as dual temp switch where unlike 95- it is one sensor with 4 pins- two go to the ECU and the other two go to the temp guage. Not to reuse one I had in my m52, I just ordered a new sensor and connector with pins. The total was around $40 for everything with shipping.

I also heard that 96+ and 95- do read differently and can be off by some amount when mixed.

Another option is to use adapter. I believe this is what you might need. Perhaps you can contact them to make sure: Click Here For Adapter

Do you have a part number for the connector and pins? I'd rather not splice.

That adapter is for an old school Chevy motor... with an SAE thread in the head.

Water Temperature Sending Unit Adapter
Part # BMW-127. Shipping weight, 1 lb

Using the BMW water temperature sending unit in the Chevrolet engine will make the BMW water temperature gauge read accurately.

The BMW water temperature sending unit has a 14mm x 1.5 thread. Stealth Conversions has a brass adapter (shown above) that accepts the BMW water temperature sending unit, and has a 3/8 pipe thread (NPT) that screws into the Chevrolet heads or intake manifold. If you have an older engine which has 1/2 pipe fittings, a 1/2 to 3/8 brass bushing can be obtained at most plumbing or automotive stores.

In the context of an engine swap getting a sensor and pigtail is not a big deal and makes the finished product a lot better, but to each his own.

Oh I know where you're coming from...

[bimerok]

Do you have a part number for the connector and pins? I'd rather not splice.

http://www.realoem.com/bmw/showparts...80&hg=11&fg=15

The sensor is item 14 Part#: 13621703993
The connector and pins item 20 Part#:12521703571 and pins 61130007657


Also, not to steal the thread, but if any one knows answer to brakes question please help Thread is here

[Pzary3233]

Awesome thank you!!

[M5Hunter]

the second temp sensor in the head(the one that goes to the ECU) is the right size and thread, but it ohms out a little different at room tempature. I am going to get some resisters and see if I can put one in-line and get it to read the same ohms, off to Radio Shack!!

In the context of an engine swap getting a sensor and pigtail is not a big deal and makes the finished product a lot better, but to each his own.

Who asked you!!! HAHAHA. The problem with just getting the new style sensor and pigtail is the gauge still wont read correctly from what I have read... I dont want to waste my time and money for it to be wrong.

[Pzary3233]

wonder how it would read with a Euro Cluster (what I have...)

[M5Hunter]

just a FYI, resisters with the other coolant temp sensor doesnt work... I was able to get the ohms the same at room temp, but when put in hot and cold water, the range was way different.

I'm thinking about milling down the sender threads and re-tapping it to the correct size.

[Pzary3233]

bummer, so the scaling is different... let us know how the milling of that goes...

[ls1bmw]

I have a 1992 and I believe I just put the sensor into an adapter and screwed it into the passenger side of the head. the ls1 needs the signal from its sensor so dont remove that

[Maynor]

If you're going to use the BMW dash temp gauge, you'll need to use the BMW sensor for the correct scaling. Most 96+ sensors will screw right into the head no sweat. I actually have one for sale with the BMW specific plug epoxied in place with the BMW specific pig tail connector is anyone's interested. No longer need it.

John
E36 LS2

[M5Hunter]

well, I ground down the treads on the sensor and bought a cheap metric tap and die set from harbor freight tool and equipment($11.99) and tapped it to m12x1.5 and it worked perfect. So for me this was a cheap alternative to buying a new sensor and harnesse.

[Pzary3233]

^ Score! that is the best way to do it for sure!

[bimerok]

Nice and on top of all you get the right sensor too

[Pzary3233]

exactly!

Now I just have to figure out what to do for the VDO gauge that I have inplace of the OBC.